Welded on blade bit



June 24, 1941. F. L. PIVOTO WELDED ON BLADE BIT I Filed Sept. 26, 1938 oi the wings.

Patented June 24, 1941 Application September 26, 1938, Serial No. 231,646

4 @laims.

the invention relates to a welded on blade bit which embodies particular and precise constructionin the manner of aflilxing th blades to the'bit and the positioning of the blades for cutting purposes.

in actual practice it has been found that welded on blade bits are only satisfactory after the blades are securely fixed to the body so as to transmit the stresses from the blades to the body and it is with this requirement in mind that the present hit and blades have been assembled.

it is one of the objects of the invention to provide a bit body having depending. wings which are offset inparallel planes with respect to each other and having a web joining the inner edges another object of the invention is to provide a bit body with depending wings and a web wherein a groove is provided along the web and on the underside oi the body to receive a blade which is thereafter welded in position so that the stresses from the blade are transmitted to the body due to the interfittlng of the blad in the groove.

other object of the invention is to provide a reeniorclng member across the diameter of the bit between the inner edges of the back-up wings so as to hold the wings rigidly in position and supported cutter blades.

Another object of the invention is to provide a groove which extends vertically with respect to a reenforcing web and horizontally with respect to the bit body which groove is to receive the edge and top of the cutter blade so 'thatweiding material may be applied to the face or the blade and the body to hold the blade in position.

. Other and further objects of the invention will be readily apparent when the following descrip- "tion is considered in connection with the accompanying drawing wherein:

Fig. 1 is a side elevation of a drag bit to which the blades have been welded and which illustrate the general arrangement and construction of the present invention.

Fig. 2 is a side elevation taken at right angles to Fig. 1.

Fig. 3 is a bottom plan view looking upwardly on the structure.

In Fig. 1 the bit body is indicated generally at 2 audit is provided with a threaded shank 3 which is tobe received in the drill collar or drill stem so that rotation may be imparted to the bit. .The usual watercourse l is formed through the shank and body and terminates in an enlarged Jill chamber 5. Leading from the chamber 5 are a plurality of discharge ports t which discharge on the oppositely lacing blades of the bit.

harticular'ajttention is directed to the configuration oi the body ii in that it has an enlarged portion "i which extends downwardly and terminates in a shoulder t. There are two oi these shoulders on opposite sides of the bit body and each extends substantially half way across the body. A flange or reamer portion it is formed at each side oi the body and extends downwardly tor the length or the body'and merges with a back-up or wing portion it, which is formed integral with the body and, as seen in Fig. 2, is divided by a groove or. recess it, which is formed transversely into the body behind the shoulder t and in front oi the front face it or the back-up wing it. In this manner a lip it is provided which defines the groove it. There are two of these groovesit which extend in wardly from the edge oi the body and they are spaced on opposite sides oi the body and on op posite sides of a diameter being materially oft set from each other, as shown in Fig. 3.

The two back-up or wine members it are opposltely facing and have their inner edges W joined by a reeniorcing web it. as seen in i Fig. 3 the back-up and theweh it form a substantlal Z and the reenforcing web tends to hold the back up members rigidly in position and it also provides a suficlent body of metal so as to have the grooves it formed laterally therein. These grooves are preferably vertical, as seen in Fig. l, and provide an overhanging lip or flange 2i which defines the groove. 7 I

The faces it of the wings are spaced in parallel planes apart from each other a width which is twice the thickness of the blades 25 which are to be afflxed to the front of the wings. Thus, when the two blades 25 are positioned as shown in Fig. 3 the front cutting faces 26 thereof will lie in substantially the same plane because of the fact that the blades are flat or straight, as seen in Figs. 2 and 3, and are on opposite ends of a diameter passing through the center oi'the bit body. In this manner the bit is balanced and the cutting blades are so disposed that they can be suitably reenforced and a sturdy and economical construction is in this manner provided.

Attention is directed to Fig. 1 wherein the edge 30 01 each of the blades 25 is shown as being disposed in the groove 20 and is overlapped by the lip 2|. The top ll of each blade is also fitted in a groove such as H and is confined by the lip I6. In this manner the blade 28 will merely be placed against the front face it of the wing and slipped into the grooves it and it. Any stresses applied to the cutting edge of the blade tending to tilt the bottom backwardly and the top forwardly as the bit rotates is resisted due to the fact that the upper end of the blade is disposed in the groove it. Any tendency of the blade to twist relative to the back-up wing is resisted by the groove 28. In this manner the stresses can be readily transferred from the blade to the body.

In order to hold the blade against sliding out of the grooves M and 20 a bead of welding material t6 can be provided along the front face Zt-of the blade and at the lip it. This welding material is not placed at the extreme upper end of the blade but is against the front face and merely holds the blade against dropping out. If desired a bead of material may be placed along the outer edge of the blade and the wing, as seen in Fig. 2, and an additional bead Ltd may be passed along the bottom edge of the wing and in this manner bond the blade thereto.

It seems obvious that with the construction such as just describedthe blade 2'5 is rigid and securely positioned in the bit body. The welding material merely holds it in place and the metal to metal contact of the blade with the body transmits the stresses due to the cutting action.

The blades may be readily removed when they are worn by merely melting down thebeads did and t3 and the blade can then be knocked out of its inserted position and a new blade quickly affixed.

Broadly the invention contemplates a welded on blade bit which will transmit the cutting stresses from the blade to the body and wherein the blades are arranged on a diameter so as to obtain the most efiective cutting action.

What is claimed is:

1. A welded on blade bit comprising a body, a downwardly extending wing on opposite sides of said body, said wings being parallel but in off set planes, a web connecting the inner ends of the wings so that in bottom plan view the wings and web have a Z configuration, and a blade welded on the front of each wing, said blades sesame being of a thickness such that the front faces of the blades will lie in substantially the same transverse plane so that the cutting surface of the bit constitutessubstantially a straight line on a. diameter across the bit, the irmer adjacent edges of said blades being spaced apart to provide a slot between the blades below said wings.

2. A welded on blade bit comprising a body, a downwardly extending wing on opposite sides of said body, said wings being parallel but in off set planes, a web connecting the inner ends 01' the wings so that in bottom plan view the wings and web have a Z configuration, and a blade welded on the front of each wing, said blades being of a thickness such that the front faces of the blades will lie in substantially the same transverse plane so that the cutting surface of the bit constitutes substantially a straight line on a diameter across the bit, the inner adjacent edges of said blades being spaced apart vto provide a slot between the blades below said wings, and an under cut slot in said body in front of each of said wings and into which the upper end of each blade is inserted prior to welding.

3. A welded on blade bit including a body, a plurality of forwardly facing wings on said body, a web joining the inner edges of said wings, a groove extending upwardly in the web and across the bottom of the body at the front iace of each wing, a blade member having its inner and upper edges seated in said groove, and welding material bonding the blade and body.

4. A welded on blade bit including a bit body, a plurality of forwardly facing wings on said body, an enlargement on the body adjacent the upper end of each of the wings, said enlargement terminating in a downwardly facing shoulder, a water course in the body, having a downwardly opening port in said shoulder, a web joining the inner edges of said wings, a groove extending upwardly in the web and across the shoulder of said enlargement at the front face of each wing, a blade member having its inner and upper edges seated in said groove, and welding material bonding the blade to the body.

FELIX L. ervo'ro. 

